Radio receivers are known. Equalizers for correcting or mitigating the effects, for example, of the channel or adjacent channel signals are also known. For example, frequency modulated (FM) receivers for use in entertainment products (automobile or home FM receivers) are known to use equalizers to effectively reduce the level of multi-path noise or adjacent channel interference and thus improve weak signal quality. Unfortunately the use of some equalizers in some instances can have unintended results. Often these unintended results arise when an equalizer is operating in accordance with presumptions about the signal to be equalized and for one reason or another, the presumptions are not an accurate reflection of present circumstances.
For example in an FM radio receiver an equalizer may be arranged to operate assuming the desired signal has a constant envelop, i.e. the equalization algorithm will seek to generate a constant envelop signal. In some cases this can lead to severe distortion or elimination of the actual desired signal. For instance, if a spurious signal is present in the desired signal as the result of a receiver performance problem or other situation, the equalizer may effectively track the spurious signal.